Check strap assembly



Jan. 11, 1966 c. R. MESSER 3,223,429

CHECK STRAP ASSEMBLY Filed May 22, 1964 POLYURETHANE IMPREGNANTPOLYURETHANE 2 IMPREGNANT 2O INVENTOR. CHESTER R. MESSER BY M ATTORNEYSUnited States Patent 3,228,429 CHECK STRAP ASSEMBLY Chester R. Messer,Concord, N.H., assignor to Page Belting Company, Concord, N.H., acorporation of New Hampshire Filed May 22, 1964, Ser. No. 369,386 3Claims. (Cl. 139-161) This invention comprises a new and improved checkstrap assembly of the type characterized by a U-shaped loop slidableupon a fixed guide rod under the actuation of a picker stick which isconfined and limited in its stroke by the loop.

Check straps of this type are subjected to very severe duty and for manyyears the textile industry has devoted extensive research and effort toincreasing the life of the strap. Every advance in that direction is ofgreat importance as it permits the employment of looms operating atincreased speed and with reduced down time. A gain in speed of only afew picks per minute may make the difference between profit and loss tothe manufacturer. It has been found, however, that every increase inloom speed magnifies the severity of duty, reduces the life of the checkstrap assembly and must be offset by effective improvement in the checkstrap itself to meet the manufac turers demand for faster operation.

I have discovered structural and functional improvements which areeffective to increase the life and efiiciency of such check strapassemblies and are therefore of outstanding importance and unexpectedbenefit to the textile industry.

The assembly employs a composite U-shaped loop of laminated straps, oneof heavy textile webbing and the other of leather. This loop isperforated at its ends and mounted to slide back and forth upon a fixedguide rod under the reversing impact of the oscillating picker stick. Inthis movement, the loop is subjected to the retarding action of frictionfingers which engage an intermediate area of the loop at one side of theplane of the picker stick oscillation. This portion of the loop is thusconstrained to travel in a path generally parallel to the plane of thepicker stick. Accordingly, the picker stick, at each end of its stroke,tends to form a hinge or angle in the loop and it is important that thestructure of the loop should permit the natural formation of such hingesat the proper location in the straps of the loop. It is equallyimportant that the loop should pass smoothly back and forth through thefriction fingers without tendency to kink or bind which would otherwiseimpart irregular movement to the loop as a whole.

In accordance with the present invention, that difiiculty is obviated,the action of the loop improved and its length of service increased byimpregnating with polyurethane or equivalent composition selected areasof the loop which impart thereto a stitfening and smoothening texture.These areas may comprise that portion of the textile loop which isengaged by the friction fingers and the two end areas of the loopadjacent to the guide rod. In this manner, the effect of the frictionfingers upon the loop is made smooth and regular, all tendency to kinkor bind is obviated and between the areas of impregnation the loopremains in condition to facilitate the formation of a natural hinge whensubjected to impact of the picker stick at each end of its stroke.

As an optional but desirable feature the entire body of the textilestrap may be impregnated with polyurethane sufliciently to impart aslight stifiening thereto with a tendency to maintain its loop shape.

These and other features and advantages of the invention will be bestunderstood and appreciated from the following description of a preferredembodiment thereof,

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selected for purposes of illustration and shown in the accompanyingdrawings, in which:

FIGS. 1 and 2 are plan views of the check strap assembly, with certainparts shown in cross section and the picker stick shown in two differentpositions.

As here shown the assembly includes a metal guide rod 10 having anelongated central lug 11 by which the rod is supported in horizontalposition from a bracket (not shown) attached to part of the loom frame.The rod is of conventional shape and carries at each end an attachedbumper head 12. Movably mounted on the rod between these two heads isthe loop-shaped body of the check strap. This comprises a pair ofsuperposed straps 13 and 14 of which the outer strap 13 is formed ofheavy webbing, such as canvas or nylon, and the inner strap 14 offlexible high grade leather. At-each end of the loop the straps 13 and14 are reinforced by overlapping tongues or helpers 15 lying inside theloop. The straps 13 and 14 together with the helpers 15 are perforatedto fit loosely upon the guide rod 10 so that the loop may slide back andforth on the rod in checking the swing of the picker stick 22.

The perforated ends of the loop are compacted and further reinforced byouter and inner clamping plates 16 and 17. These may be formed of stifffibrous or plastic material. The inner plates 17 are notched at theirinner edges to clear the guide rod 10 and the outer reinforcing plates16 are perforated to clear the guide rod and flared outwardly. Thecomponents of the loop are all permanently bonded together at each endby rivets or other fasteners. The bound ends of the loop extend beyondthe guide rod 10 where they are connected by a tie member 18 thatconverts the loop into D-shaped formation. The tie member 18 is heldunder tension by and between the ends of the loop.

As herein shown, the loop is engaged at the other side of the guide rod10 by friction fingers 20 and 21 which exert a frictional retardingaction on the loop as it travels back and forth under the actuation ofthe picker stick 22. The friction fingers are somewhat rounded forengagement with the loop and are pressed into yielding frictionalengagement by means not herein shown.

In FIG. 1, the picker stick 22 is represented as moving in its powerstroke to actuate the shuttle and at this point of the cycle it has notyet engaged the loop which remains in the position to which it has beenmoved by the picker stick in its idle stroke.

In FIG. 2, the picker stick is represented at the end of its powerstroke where it has already contacted, the shuttle and moved the loop toits extreme left hand position causing the formation of a hinge at aboutits point of contact.

As herein shown the textile strap 13 is impregnated in the darkenedareas with polyurethane. These areas include that portion of the strapwhich is engaged in any time by the friction fingers and the perforatedend portions of the strap. A polyurethane impregnant solution containingabout 40% solids has been found suitable for effecting outstandingimprovement of the check strap assembly in the respects above noted andalso in substantially reducing wear and unraveling of the textile strapin the vicinity of the holes for passage of the guide rod.

If desired the entire body of the strap 13 may be lightly impregnated inthe polyurethane, as by treating the undarkened areas with a solution of20% solids. This tends to maintain the straps in their loop-shapedformation while the heavier impregnation of the darkened areasfacilitates the creation of a smooth wave of deflection under the actionof the friction fingers 20, 21. While polyurethane is the preferredimpregnant any equivalent thermosetting resin could be employed withinthe scope of the invention.

Having thus disclosed my invention and described in detail anillustrative embodiment thereof, What I claim as new and desire tosecure by Letters Patent is:

1. In a check strap assembly, a composite loop comprising a strap ofleather and a strap of textile Webbing, the loop being perforated at itsends and mounted upon a fixed guide rod to slide under the actuation ofa picker stick, together with stationary friction fingers engaging anintermediate area of the loop; that improvement in which the strap oftextile webbing is impregnated in an intermediate area within range ofsaid friction fingers with polyurethane, thereby smoothening andstiffening the strap, an d reducing tendency to-ripple in passingthrough said fingers while leaving the strap free for the formation of anatural hinge in its unimpregnated portions.

2. In a check strap assembly, a composite loop as defined in claim 1,further characterized in that the end portions of the textile strap arealso impregnated with polyurethane thus leaving spaced unimpregnatedareas of the strap for the formation of natural hinges.

3 In a check strap assembly, a U-shaped strap of textile Webbingimpregnated throughout its length with cured polyurethane and havingperforated end areas and an intermediate-area impregnated with asubstantially greater concentration of polyurethane than the remainderof the strap thereby facilitating the formation of hinges in the areasof less impregnation.

References Citedby the Examiner UNITED STATES PATENTS 2,721,811 10/1955Dacey et al. 2,775,264 12/1956 R-ockoif 139-161 2,822,828 2/1958 Crocker139161 2,884,961 5/1959 Plante et al. 139166 3,114,397 12/1963 Messer139161 3,126,922 3/1964 Randlett et al 139-165 FOREIGN PATENTS 745,2242/ 1956 Great Britain.

DONALD W. PARKER, Primary Examiner.

1. IN A CHECK STRAP ASSEMBLY, A COMPOSITE LOOP COMPRISING A STRAP OFLEATHER AND STRAP OF TEXTILE WEBBING, THE LOOP BEING PERFORATED AT ITSENDS AND MOUNTED UPON A FIXED GUIDE ROD TO SLIDE UNDER THE ACTUATION OFA PICKER STICK, TOGETHER WITH STATIONARY FRICTION FINGERS ENGAGING ANINTERMEDIATE AREA OF THE LOOP; THAT IMPROVEMENT IN WHICH THE STRAP OFTEXTILE WEBBING IS IMPREGNATED IN AN INTERMEDIATE AREA WITHIN RANGE OFSAID FRICTION FINGERS WITH POLYURETHANE, THEREBY SMOOTHENING ANDSTIFFENING THE STRAP, AND REDUCING TENDENCY TO RIPPLE IN PASSING THROUGHSAID FINGERS WHILE LEAVING THE STRAP FREE FOR THE FORMATION OF A NATURALHINGE IN ITS UNIMPREGNATED PORTIONS.